Control for fuel economizers



1944- R. P. SKERRITT CONTROL FOR FUEL ECONOMIZERS 2 Shets-Sheet 1 FiledApril 8, 1942' Gttomegs Nov. 14, 1944. R. P. SKERRITT CONTROL FOR FUELECONOMIZERS 2 Sheets-Sheet 2 Filed April 8 1942 fa zs/zeri'i? @aw 6 7Gttomegs Patented Nov. 14, .1944

. 2,352,940 con'raon FOR rusnnconomznas Roy r. Skerrltt, Detroit, Mich.

Application April 8, 1942, Serial No. 438,148

4 Claims.

The present invention relates to heat economizers, and more particularlyto a control therefor.

- The primary object of the invention is to provide a device forutilizing the heat carried oil in gaseous form from a furnace vor heaterby passing said gases of combustion through a heat exchanger havingmeans for conveying heated air to desired locations in a house orbuilding.

Another object of the invention, is to provide a device as set forth inthe preceding object which is particularly applicable to furnacestructures which have been converted from a coal fired boiler to a gasor oil type burner so that the heat from the gaseous products ofcombustion passing through the furnace will be utilized instead of beingconducted to the atmosphere through the flue and stack.

Another object of the invention is to provide a heat exchanger of uniqueconstruction having a passageway communicable with the furnace flue andpassages extending transversely thereof for conducting air through saidexchanger so that the air exhausting therefrom may be used for heatingrooms in addition to the conventiona1 house heating system.

Another object of the invention, is to provide a heat exchanger of theabove mentioned type having a force feed fan which is adapted to becontrolled by a thermostat in the flue pipe on 80 the outlet side of theheat exchanger so that in the absence of heat in said flue, theoperation of the fan or other air force feed means will be discontinuedto prevent the feeding of cold air to the room or rooms coupled to theheat exchanger.

Another object of the invention, is to provide a heat economizer whichis adapted to be employed for supplying heated air to a room of abuilding in which the furnace control thermostat is placed so that saidroom will receive additional heat and the furnace control thermostatwill govern the furnace heater in accordance with said heat, whereuponan ideal heating condition will exist inwhich one of the rooms will bemaintained at a higher temperature, such as the living room so that thebedrooms of the building will not be overheated and will be properlyconditioned for healthful sleeping.

Other objects and advantages of the invention will become apparentduring the course of the following description of the accompanyingdrawingswherein: I

Figure 1 is a side elevation of the device embodying the inventionillustrating the same coupled with a conventional hot water heatingsystem and showing diagrammatically the manner of supplying additionalheat to one of the rooms in a building;

Figure 2 is a vertical cross sectional view taken on line 2-2 of Figure1 looking in the direction ofthe arrows illustrating the transverse airpassage through the heat exchanger and the manner of creating a forceddraft therethrough;

Figure 3 is a top plan view of the heat exchanger partly broken away andgreatly enlarged to further illustrate details thereof.

Figure 4 is a vertical cross sectional view taken on line 4-4 of Figure3 looking in the direction of the arrows showing the structure of theheat exchanger per se;

Figure 5 is a longitudinal cross sectional view taken on line 5-5 ofFigure 3 looking in the direction of the arrows illustrating the forceddraft means and showing a humidifier on the outlet side of the heatexchanger, and;

Figure 6 is a perspective view of the heat exchanger illustratingportions of the casing broken away to clearly show the constructionthereof.

Figure 7 is a side elevation of the air supply valve.

General arrangement -'I'he invention comprises a rectangular casingadapted to'be interposed in the flue pipe of a furnace, which furnacehas been converted to a gas or oil type heater so that the furnace gaseswill travel through said rectangular casing and cause heat to betransferred .by induction to transversely extending passageways throughwhich air is conducted by means of a blower or other force feed means.The heated air from the rectangular casing is then conducted to one ofthe rooms of a building for supplying additional heat thereto, whichadditional heat will raise the temperature of the room and allow theburner control or thermostat therein to be more easily-satisfied, thusresulting in a further saving of fuel and the prevention of houseoverheating. Further, the invention consists bf providing thermostaticmeans in the'f'urnace flue on the outlet side of the heat exchanger forcon trolling the force draft means so that said forced draft means willcease operation inthe absence of heat in the flue pipe below apredetermined degree. It is contemplated that the thermostat operate tocut off the force feed means when the temperature in the flue drops to apredetermined degree dependent upon the operation of the furnace heaterso that cold air will be prevented from being forced through theexchanger and into the room, and the gases will be prevented from beingcondensed which condensation it allowed would result in deleteriouseifects and damage to the casing structure through corrosion.

Detailed descriptionv In the drawings, wherein for the purpose ofillustrating the invention and wherein like reference characters will beemployed to designate like parts throughout the same, the referencecharacter it will generally be employed to designate a conventionalfurnace having a boiler structure coupled to a radiator il in a room l2by means of a pipe IS. The room l2 may constitute a living room of abuilding above the cellar foundation H in which\ the furnace II) isusually placed.

The invention is adapted to be applied to heating systems in which thefurnace in has been converted to a gas or oil fired type and for thepurpose of illustration, an oil burner type heater i5'is shown in Figure1 having a blower l5 supported by a suitable pedestal II. The blower itof the oil burner is controlled by means of a switch mechanism i8mounted thereon in the form of a relay so that closing of said switchwill establish electrical contact with the supply lines 19. A thermostatis located in the room l2 adjacent the radiator II and is coupled to therelay switch l8 by line wires 2| so that said thermostat may operate therelay l8 and thereby control the motor blower i6.

In converted furnaces of the above type, the outlet for the burned gasesis placed adjacent the top of the furnace and as indicated in Figure 1,includes a. flue pipe opening 22 for receiving a flue pipe adapted to becoupled to the stack extending through the foundation wall l4.

The invention includes a heat exchanger generally designated by thereference character 24 and said heat exchanger is shown indetail inFigures 2 to 6 inclusive. The heat exchanger comprises a casing having abottom wall 25 and a top wall 26 connected by end walls 21 and 28. Theend wall 21 is provided with converging portions connecting a circularflue pipe section 29 which is adapted to be inserted in the flue pipeopening 22 0f the furnace III. A damper 30 is interposed in the fluepipe section 29 and is provided with an operating handle 3| so that thedamper may be swung on its pivot to control the flow of hot gases to thecasing 24. The opposite wall 28 is provided with a tubular section 32centrally mounted thereon which has its end as at 33 extending into thechimney or smokestack of the building, having communication therewiththrough the foundation wall I4.

Convergent side walls 35 connect the end walls 21 and 28 as well as thebottom and top walls 25 and 26, and said convergent walls terminate inacircular flange portion 36, further tapered at 35a, closed by aperforated end wall 36a, providing an opening in the casing for thepassage of air currents therethrough. A disk valve 35b is rotatablysecured to the perforate end wall 38a so that the perforation in saidwalls may be brought into registry to control the volume of air throughthe air passageway and thereby prevent the flue gases from being cooledto such an extent as to cause damage to the casing structure from thecondensation of said flue gases. Monuted on the circular flange 35 is amotor supporting bracket 31 secured in place by means of bolts or thelike as at 38 and the upper end of the bracket 31 as at 21 is adapted tosupport a motor 40 having an armature shaft 4i provided with a fan 42the hub of which as at 42 is rigidly secured to the armature shaft torotate therewith. The opposite side wall of the casing as at 44 isprovided with a centrally disposed tubular section 45 for connectionwith a vertical air pipe 45 having an elbow 41 for connection with a hotair register 45 by means of an L-shaped connector 45, the foot portionof which as at extends through the floor l2 of the room so that hot airmay be conducted to said room under forced draft from the fan 42.

Mounted within the heat exchanger casing 24 is a pair of oppositelydisposed header plates 50 and 52 which are identical in structure andare provided with openings 53 for receiving the ends of flat heatexchanger tubes 54. The tubes 54 are formed from thin sheet metal andprovide transverse passageways 55 for conducting air currents throughthe casing in the direction of the arrows indicated in Figures 5 and 6.The openings 53 provide relatively long spaced header strips 58 forconnecting the ends of adjacent tubes to provide hot gas passageways 51arranged alternately on opposite sides of the passageways 55 andrelatively flat plate-like tubes 54. This structure provides for theallowance of heat induction between the passageways 51 and thepassageways 55 extending at right angles thereto so that heat exchangewill occur and the air forced through the passageways 55 will reach arelatively high temperature upon the outlet side 45. Since the heatconduction surfaces are equal, the air on the exhaust side 45 of thecasing will reach a temperature equal to half the temperature of the hotgases combined with the temperature of the air on the inlet side 36 ofthe casing.

The outlet side 45 of the casing is formed with a humidifier chamber 50by spacing the header plate 52 from the side wall 54 a sufficientdistance as is shown clearly in Figure 3. An opening 6! is formed to oneside of the end wall 28 and said opening is preferably formedrectangular in shape for receiving a humidifier trough 52 extending thefull width of the humidifier chamber 50. The trough 52 is provided witha marginal upstanding side wall 63 and connecting the upstanding idewall 63 is a ledge portion 54 to which is hinged a cover 55 as at 55.The trough 82 may be inserted in the rectangular opening 5| so that theledge 64 projects therein to prevent the escape of hot air from findingits way through the trough and to the atmosphere. The humidifier troughmay be filled with water by raising the cover 55 and filling the troughto the desired level.

Mounted in the tubular flue section 32 is a thermostatic control member61 which projects into the casing into the path of the hot gases passingtherethrough as indicated in Figure l. A bushing 58 is formed on thethermostatic member 51 and is provided with a casing 59 in which islocated a switch element having contacts Iii which are in series with asource of current supplied through a lead line H and connecting themotor 40 by a lead line'12. A lead line 13 is connected to the motor 40to the opposite side of the power source to complete the circuit.

Mode of operation For consideration of the operation of the invention,it will be first assumed that the furnace l0 and the burner I6 areinoperative by reason of the heat in the room 12 satisfying thethermostat 20. Under these conditions, the thermostat 61 will be in aposition to maintain the normally open switch 69 in its open positionwherein the motor will be at rest as will also be the fan 42.

so that heat conducted thereto from the flue gases traversing thepassageways 51 will cause said air to be heated and conducted to thehumidifier chamber 60 where it is passed over the humidifier tray 62 andthence to the register 48 in the room II.

In this manner, additional heat is supplied to the room I! whereby thetemperature therein will be raised by the heat from the radiator II andalso by the heat entering the room through the register 48. Obviously,the room temperature will reach the desired degree more quickly so thatthe thermostat will be satisfied and cause the relay l8 to cut theburner blower l6 out of the supply line If! and thereby stop theoperation of the furnace and burner l5. When this condition exists, heatfrom the products of combustion is likewise ended and the temperature inthe circular flue section 32 will start to fall so that the switchwithin the casing 69 will open and cut off the motor 40 and the forceddraft operation of the fan 42. The cycle of operation above describedwill continue to maintain the room l2 at a proper temperature with asmaller consumption of fuel in the burner l5 resulting in a considerablesaving of maintenance cost.

It isto be understood that the form of the invention herewith shown anddescribed is taken as a preferred embodiment of the same and thatvarious changes in the shape, size and arrange- I ment of parts may beresorted to without departing from the spirit of the invention or thescope of the subioinedclaims.

What I claim is:

1. A. heat exchanger comprising a rectangular casing, a plurality ofrelatively flat air tubes extending transversely through said casing, aplurality of contiguous flue gas passageways formed at right angles tosaid air tubes, means withinsaid casing on the inlet side of saidrelatively flat air tubes for creating a forced draft of air.

therethrough and a humidifier within said casing on the outlet side ofsaid relatively flat air tubes for humidifying the heated air passingfrom the heat exchanger through said contiguous flue gas passageways.

2. A heat exchanger comprising a rectangular casing having a series ofspaced relatively flat passageways for flue gases, a series ofrelatively flat transversely extending tubes mounted in said heatexchanger forming air passageways therethrough' and betweensaid seriesof spaced relatively flat flue passageways, a blower on one side of theheat exchanger within the casing for creating a forced draft of airthrough said tubes and a humidifier on the outlet side of saidtransversely extending air tubes within the casing for humidifying theheated air, said humidifier being located beneath the outlets of themajor portion of said air tubes in air contact relation thereto.

3. A heat exchanger comprising a cruciform casing having aligned fluepassageways, a series of spaced-relatively flat transversely extendingtubes mounted in said casing, header plates for the ends of said tubes,the spaces between said tubes being in communication with said fluepassageways in the casing and providing flue gas conduits, a' blowersupported in the casing at the air inlet side of said tubes for creatinga forced draft of air through said tubes, 8. humidifler mounted withinsaid casing at the outlet side of the transversely extending tubes andheat responsive means in the outlet side of the flue passagewayresponsive to temperature changes within said flu'e passageway forcontrolling the blower,

4. A heat exchanger comprising a cruciform casing having aligned flueinlet and outlet pipes. a series of relatively flat transverselyextending tubes mounted in the casing between said flue inlet andoutlet, header plates having openings for receiving said tubes, a blowerwithin the casing and one of said header plates on the inlet 45 side ofthe relatively flat transversely extending tubes for creating a forceddraft of air through said tubes, a humidifier located within the. casingbetween the other header plate and the outlet side of the relativelyflat transversely extending tubes and a thermostatic switch mounted inthe direct path of'gases in the outlet flue passageway responsive totemperature changes therein for controlling said blower.

nor a smarrr.

